T H E
D E T A I L
Monday, April 29, 2002
BREAKING NEWz you can
Last Chance to Join First
Round McKie Print Petition
The list closes on Wednesday, as the debate in Scottish Parliament
approaches. The current count is about 120 names on the petition.
ANOTHER CSI !?! The
CBS team gears up for "CSI:
MIAMI." If Vegas Metro is the consultant for CSI: Vegas, has
anybody heard who (if anyone) from Florida is consulting for the Miami
show? If not, who should we ask to volunteer (probably from Miami-Dade)?
of human remains in belly of shark - Singapore
Strait Times - 23 Apr 2002
... distinctive tattoos. A rope was tied to the wrist. The
victim was identified from
as Edward Smith, but no one was ever convicted of his murder. 'We ...
Good morning via the "Detail," a weekly e-mail newsletter that
greets latent print examiners around the globe every Monday morning. The purpose of the Detail is to help keep you
informed of the current state of affairs in the latent print community, to
provide an avenue to circulate original fingerprint-related articles, and to
announce important events as they happen in our field.
For the last two
weeks, we have looked at the McKie comparison statement and petition available
for latent print examiners worldwide to support. There are only a few days
left to get your name on the 'first round' list, so please act
accordingly. This week, we turn our attention to a processing technique
that Dave Wade is doing a great job at spreading the word about.
Processing Tape with Titanium Dioxide (Tio2)
In August of 2001, I was
fortunate enough to attend the Administrative Advanced Latent Fingerprint School
at the FBI Academy. One of the
requirements of this course is that you do a research project on a fingerprint
related topic. I chose
“Development of Latent Prints on Adhesive Material”.
While researching the topic, I read an article that mentioned using SPR
in place of Sticky-Side Powder for processing electrical tape.
The reason for this was that it was somewhat easier to see than the
Sticky-Side Powder. I mentioned
this to Carl Keener, who was one of the instructors for the course.
He said that SPR is nearly as dark in color as Sticky-Side Powder.
He mentioned that he had some of Sirchie’s white SPR in the lab, but he
had not had much success with it.
Sirchie’s white SPR comes in a liquid form, which contains a small amount of
titanium dioxide (TiO2), tergitol, and water.
When I tried using it on black electrical tape, it simply turned the tape
gray. I then added some Kodak
Photo-Flo to the SPR. I processed a
piece of electrical tape by agitating it in the mixture to keep the TiO2
particles in suspension. After about a minute, I removed the tape and allowed the
mixture to drain off. Very clear
white prints were visible on the tape.
Latent print developed with TiO2 powder
on the adhesive side of black electrical tape
After returning to Albuquerque, I continued experimenting with this process.
Since TiO2 is a common pigment in paint, I contacted a local
company that makes paint and explained what I was working on.
They gladly provided me with a large bag of Kerr-McGee CR-880 titanium
dioxide. I found that simply using
the TiO2 powder in place of Sticky-Side Powder produced excellent
Nice level three detail developed with
TiO2 powder on adhesive side of
black electrical tape
Mix the powder with a 50/50 mixture of water and Kodak Photo-Flo until you have
a paste. Apply it to the tape, just
as you would Sticky-Side Powder, but apply it to both sides of the tape.
Rinse the paste off the tape and the developed latents will be visible. This process will develop latents on both sides of the tape.
Allow the tape to dry. The
developed latents will be delicate and can be easily wiped off, especially on
the non-adhesive side, so be careful. This
method works especially well on the adhesive side of electrical tape and the
non-adhesive side of duct tape. If
you are processing duct tape, I recommend processing the adhesive side with
Sticky-Side Powder and the non-adhesive side with TiO2 paste.
The two processes will not interfere with each other.
Latent prints developed on the NON-adhesive
side of duct tape with
You can also make a solution in a tray to process larger items or pieces of
tape. Simply pour a 50/50 mixture
of water and Kodak Photo-Flo into a tray and stir in TiO2 powder
until the mixture looks like milk. Agitate
the item to be processed in the mixture for approximately 2 minutes, then rinse.
Allow the item to dry, then examine for developed latents.
These processes also work well on
plastic bags and cellophane.
You must use a rutile form of TiO2,
not an anatase form. One of the
best is Kemira 820. It can be
obtained from Steve Parker at Kalamazoo Paper Chemicals for about $4 a pound.
Contact him via e-mail at KalPaperChem@compuserve.com.
I have successfully used this process many times to develop workable latents on
electrical tape, duct tape, and plastic bags.
Recently, one of our Field Investigators, Kevin Sanchez, brought me a
shattered car window from the scene of an auto burglary.
The offender had apparently applied black duct tape to a window of a
Sheriff’s Department vehicle before breaking it.
He then took the shotgun out of the vehicle, but left the broken window
with the tape on it. I left the
tape as it was, still attached to the glass, and processed the non-adhesive side
with a TiO2 paste. Numerous
white prints of AFIS quality were
visible on the tape. I immediately
entered one print into AFIS, which hit on a suspect.
article on this process will be in an issue of the Journal of Forensic
Identification later this year. If
you have any questions, please contact me via e-mail at DWade@cabq.gov
or visit my website at www.whiteprint.com.
CLPEX.com this week...
Updated the Articles page to include Dave Wade's TiO2
Updated the Detail Archives
As usual, the CLPEX chat
is available this week for informal banter about the Weekly Detail, as
is the onin.com forum (http://onin.com/fp/wwwbd/)
for other discussion. If YOU have a processing technique that you
have tested, validated, etc... and would like to share, please e-mail me.
Spreading the word about new techniques is one of the main reasons I created the
Feel free to pass the link to The Detail along to other examiners. This is a
free service FOR latent print examiners, BY latent print examiners. There are no
copyrights on The Detail, and the website is open for all to visit.
If you have not yet signed up to receive the
Weekly Detail in YOUR e-mail inbox, go ahead and join
the list now so you don't miss out!
Until next Monday morning, don't work too hard or too little.
Have a GREAT week!